1. Field of the Invention
The present invention relates to a write-once optical disc and a method for managing spare area thereof, and more particularly, to a method for allocating a spare area to reduce or expand the allocated spare area.
2. Discussion of the Related Art
As optical recording mediums, optical discs having a large capacity of data recorded thereon are widely being used. Among them, a new high-density digital versatile disc (HD-DVD), for instance, a blu ray disc (Blu-ray Disc) that can record and store video data of high quality and audio data of high fidelity for a long term period has been recently developed.
The blu-ray disc employing a next-generation HD-DVD technology is a next-generation optical recording solution that can store data to such a degree remarkably exceeding the storage capacity of a conventional DVD, and a technical specification of international standard for HD-DVD has been recently regulated.
Related with this, various standards related with the blu-ray disc are prepared, and various standards for a write-once blu-ray disc (BD-WO) are being prepared following a rewritable blu-ray disc (BD-RE).
FIG. 1 schematically illustrates a structure of a recording area of a rewritable blu-ray disc (BD-RE). FIG. 1 illustrates, for example, a structure of a recording area of a single-layer disc having one recording layer. The disc is distinguished when viewed from the inner periphery thereof as a lead-in area, a data area and a lead-out. Further, the data area is provided with an inner spare area (ISA0) and an outer spare area (OSA0) respectively disposed at the inner and outer peripheries to replace a defective area. A user data area for recording user data therein is provided between the spare areas.
While data is recorded on the rewritable blue-ray disc (BD-RE), if there exists the defective area in the user data area, data recorded in the defective area is transferred to and replaced and recorded in the spare area. Additionally, position information related with the defective area, that is, position informations related with the defective area and a replacement area and the like is recorded in defect management areas (DMA 1, 2, 3, 4) provided for the lead-in/out areas to perform defect management. The BD has a cluster as a minimal recording unit recorded thereon. One cluster is comprised of total 32 sectors, and one sector is comprised of 2048 bytes.
Since rewriting can be performed even in any area of the rewritable disc, an entire area of the disc can be used randomly irrespectively of a specific recording manner. Also, since the defect management information can be rewritten even in the defect management area (DMA), it does not matter even though only a predetermined size of the defect management area is provided. In particular, the BD-RE allocates and uses 32 clusters as the defect management area (DMA).
However, in the write-once disc, since writing can be made once on the disc, the recording manner is not only much limited, but also the defect management becomes one of important matters when data is recorded on a high-density write-once disc such as the recent BD-WO. Accordingly, even the write-once disc needs a management area to record information on defect management and disc management, and especially the write-once optical disc needs a larger management information recording area with comparison to the rewritable disc due to the property of ‘write-once’. Like the rewritable optical disc, the write-once optical disc also needs a larger spare area than the rewritable optical disc so as to enable the defect management and the (logical) overwriting function.
However, since any of currently published regulations on the conventional write-once optical disc (ex. CD-R, DVD-R etc.) does not refer to a case where the spare area and the defect management area are both provided, preparation of new unified regulations is required for satisfying the above-mentioned requirements.